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kernel/linux-imx6_3.14.28/fs/befs/io.c 1.75 KB
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  /*
   * linux/fs/befs/io.c
   *
   * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
   *
   * Based on portions of file.c and inode.c 
   * by Makoto Kato (m_kato@ga2.so-net.ne.jp)
   *
   * Many thanks to Dominic Giampaolo, author of Practical File System
   * Design with the Be File System, for such a helpful book.
   *
   */
  
  #include <linux/buffer_head.h>
  
  #include "befs.h"
  #include "io.h"
  
  /*
   * Converts befs notion of disk addr to a disk offset and uses
   * linux kernel function sb_bread() to get the buffer containing
   * the offset. -Will Dyson
   *
   */
  
  struct buffer_head *
  befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
  {
  	struct buffer_head *bh = NULL;
  	befs_blocknr_t block = 0;
  	befs_sb_info *befs_sb = BEFS_SB(sb);
  
  	befs_debug(sb, "---> Enter befs_read_iaddr() "
  		   "[%u, %hu, %hu]",
  		   iaddr.allocation_group, iaddr.start, iaddr.len);
  
  	if (iaddr.allocation_group > befs_sb->num_ags) {
  		befs_error(sb, "BEFS: Invalid allocation group %u, max is %u",
  			   iaddr.allocation_group, befs_sb->num_ags);
  		goto error;
  	}
  
  	block = iaddr2blockno(sb, &iaddr);
  
  	befs_debug(sb, "befs_read_iaddr: offset = %lu", block);
  
  	bh = sb_bread(sb, block);
  
  	if (bh == NULL) {
  		befs_error(sb, "Failed to read block %lu", block);
  		goto error;
  	}
  
  	befs_debug(sb, "<--- befs_read_iaddr()");
  	return bh;
  
        error:
  	befs_debug(sb, "<--- befs_read_iaddr() ERROR");
  	return NULL;
  }
  
  struct buffer_head *
  befs_bread(struct super_block *sb, befs_blocknr_t block)
  {
  	struct buffer_head *bh = NULL;
  
  	befs_debug(sb, "---> Enter befs_read() %Lu", block);
  
  	bh = sb_bread(sb, block);
  
  	if (bh == NULL) {
  		befs_error(sb, "Failed to read block %lu", block);
  		goto error;
  	}
  
  	befs_debug(sb, "<--- befs_read()");
  
  	return bh;
  
        error:
  	befs_debug(sb, "<--- befs_read() ERROR");
  	return NULL;
  }